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Cumulative Gas Mileage (Gas MPG) Thread

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Old 11-30-2004, 06:21 AM
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Yeah, it was a 20 h.p. increase via G-Tech measurement, not dyno, but the e.t. drop was consistent with a 20 h.p. gain. That just means that there was either 20 h.p. gained at the flywheel or through more efficient driveline operation. Either way, dropping 2-3 tenths is a gain to me and the car drives a whole lot better.

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Old 11-30-2004, 09:45 AM
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Originally Posted by rx8wannahave
You know I was going to throw my two cents into this topic...LOL :D

I wont say much but I wonder what a Mazda engineer, CEO, etc would pay attention to with their next update of the RX8 if they visited this site.

MORE TORQUE
BETTER FUEL ECONOMY (or at least a 17 gallon tank)
MORE HP

Now go...go Mazda...and build a EVEN BETTER RX8....

No problem, but if I recall you don't want to pay even $30k for an RX8- how do you expect even more engineering to be put into this car for free? I for one don't want to see the RX8 follow the Miata's lead, going from an inexpensive fun car to an overpriced one. We don't need a $40k RX8- that's where the next RX7 should come in.


And to the original poster- cruising at 80mph is not going to get you the best gas mileage- 19-20mpg sounds about right for that speed. The sweet spot is around 72mph or lower, right before the secondary intake path and injectors open up (~3750rpm in 6th). However, I don't think it's worth driving in the slow lane just to save a couple of bucks in gas... that's what Camrys and Minivans are for.
Old 11-30-2004, 10:03 AM
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Originally Posted by amartin
its not the $ its the fact I have to freaking stop and get gas so often.
Getting colder, eh?! :D
Old 11-30-2004, 11:55 AM
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Originally Posted by G8rboy....that's what Camrys and Minivans are for.

I always see these vehicles blocking the fast lanes all the time.
Old 11-30-2004, 03:06 PM
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How, or even..WHY should I drive 60 or 65??

The speed limits on the highways here in Texas are 70-75mph...doing 80-85 is pretty much the "norm"

..and..shifting at 3k.. I tried it yesterday... you gotta be kidding me-- HOW can you people possibly drive shifting at 3k? Thats just silly. I watch an old woman in a wheelchair pass me shifting like that.
Old 11-30-2004, 03:19 PM
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No problem, but if I recall you don't want to pay even $30k for an RX8- how do you expect even more engineering to be put into this car for free?
I don't want to pay that cause I don't got that type of money, but not because $30,000 is a bad price for the RX8. I think the RX8 going for $27,000-$32,000 is a great bang for the buck car.

Now, tell me cause I'm not sure...don't car companies continue to research their cars after they go on sale? So, if owners complain about the same things over and over then I think Mazda would pay attention. If I ran it...I would, but that's just me...

A bigger gas tank would cost about what? $50 or so....that's worth it
250HP & 180ft/t would cost another...what, $300-500...that's worth it also

Trust me, I don't want the RX8 to grow into the 40's because then the car would lose alot of its appeal. But, I think Mazda improveing it over time is the smart thing to do instead of just relaxing until the sales drop dead. Just my two cents...

Note: I just test drove the RX8 this past Friday and I think I understand now that shifing at 3K might not be realistic. 3.7-4K....might be, but not 3K
Old 11-30-2004, 06:33 PM
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My first tank, I got 17 MPG city. Then again, I was shifting at 3K during the breakin period. That all ended at 600 miles. Over the Thanksgiving Holiday, took my first long highway trip. Was doing better than 80 most time (70%) and basically hovered around 90 with the occasional dash to 100-110. Got about 18 MPG. Got 19.2 MPG on one tank. Not disappointed as I was moving.

I tried to set the cruise at 68 for a full tank just to see the improvement... NO patience.. So I'll have to try minivan highway driving some other time.

I agree with others, MPG doesnt matter to me, the frequency at the pump does.

My next mod, a la Mad Max.
Attached Thumbnails Cumulative Gas Mileage (Gas MPG) Thread-max2.jpeg  

Last edited by valpac; 11-30-2004 at 06:37 PM.
Old 11-30-2004, 06:37 PM
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Everyone seems to forget one simple fact... mpg and hp are intertwined. IOW we are getting less fuel effeciency for the same reason that we have less hp. When we start getting better fuel economy I suspect we will be closer to the 250 propoesed hp.
Old 11-30-2004, 06:40 PM
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Originally Posted by 93rdcurrent
Everyone seems to forget one simple fact... mpg and hp are intertwined. IOW we are getting less fuel effeciency for the same reason that we have less hp. When we start getting better fuel economy I suspect we will be closer to the 250 propoesed hp.
I'd like to check out my AFR sometime to see what kind of numbers my stock RX-8 is doing. Depending on the numbers, I may be persuaded to go the Canzoomer route...

~ Matt
Old 11-30-2004, 06:41 PM
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Originally Posted by Vaillant
I'd like to check out my AFR sometime to see what kind of numbers my stock RX-8 is doing. Depending on the numbers, I may be persuaded to go the Canzoomer route...

~ Matt
I'll be talking with CZ next spring. Meant to do it this year but had too many obligations on my income to follow through.
Old 11-30-2004, 06:49 PM
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Originally Posted by rx8wannahave
...

A bigger gas tank would cost about what? $50 or so....that's worth it
250HP & 180ft/t would cost another...what, $300-500...that's worth it also
...
Its not a matter of larger.. its a matter of real estate. The engineering required to modify existing structure and systems to accommodate the changes you mentioned make it cost prohibitive. Compromises require extensive engineering . The only way is to increase selling price.

An example: I work on the C-130 Hercules a/c. When Lockheed decided to make a new model (the J), they decided on more powerful engines. Engine cost was minute compare to the beef-up, system, fuel, wing engineering changes required to make the new engines a reality. Four new engines ($1M per times 4) made the a/c cost jump approx. $30M.
Old 11-30-2004, 06:53 PM
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And how would they redistribute the weight? I still insist on having my 50/50 weight distribution since that was the only reason I didn't get the M3 instead. Both cars handle pretty close to the same in corners.
Old 11-30-2004, 07:51 PM
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i tried shifting at 3000, got 14.7 mpg. explain that one?
Old 11-30-2004, 08:15 PM
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Originally Posted by amartin
How, or even..WHY should I drive 60 or 65??

The speed limits on the highways here in Texas are 70-75mph...doing 80-85 is pretty much the "norm"

..and..shifting at 3k.. I tried it yesterday... you gotta be kidding me-- HOW can you people possibly drive shifting at 3k? Thats just silly. I watch an old woman in a wheelchair pass me shifting like that.
Ok fine. Try 70 mph on cruise control for a fwy trip over 100 miles. Just do it to see if your car is defective or not. Do it once. Do it twice. And just see.
Old 11-30-2004, 08:16 PM
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Originally Posted by irfan
i tried shifting at 3000, got 14.7 mpg. explain that one?
Do the 20 pump test to reset the ECU. Then go on a distance trip on cruise. Tell us what you get. If you're still at 14-15 MPG, I'll give you a free bag of lemons.
Old 12-01-2004, 08:16 AM
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Do the 20 pump test to reset the ECU
Can someone please explain this to me? What is this 20 pump ECU reset thing? Why does this happen, is it documented by Mazda, what are you telling the ECU when you do this?

Thanks for the help!
Old 12-01-2004, 09:24 AM
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Originally Posted by rx8wannahave
Can someone please explain this to me? What is this 20 pump ECU reset thing? Why does this happen, is it documented by Mazda, what are you telling the ECU when you do this?

Thanks for the help!
Maybe I am crazy but, I believe you are clearing a memory portion that among (maybe) other things stores the crank position (or something like that!) - Or was it that it clears an entire portion of the ECU's memory..? OK, I know its posted somewhere in here.

On top of that, if after pumping the brakes 20 times one of the cluster needles sweeps back and forth a few times, is indicative of a certain calibration level on the ECU. That's about all I can remember.
Old 12-01-2004, 09:55 AM
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Originally Posted by RX8-TX
Maybe I am crazy but, I believe you are clearing a memory portion that among (maybe) other things stores the crank position (or something like that!) - Or was it that it clears an entire portion of the ECU's memory..? OK, I know its posted somewhere in here.

On top of that, if after pumping the brakes 20 times one of the cluster needles sweeps back and forth a few times, is indicative of a certain calibration level on the ECU. That's about all I can remember.
Pretty much correct- it was found in one of the TSB's as a way to clear the ECU's NVRAM that contains the the eccentric shaft (our equivalent to a crank's CAS info)position info:
http://www.finishlineperformance.com...ocs/01-007.htm

If you have the 'L' PCM calibration or higher, the OPG needle will sweep to it's high resting position and back if the NVRAM clearing is successful. I don't know if it's been proven that this resets the portion of the ECU's ram that collects driving habits and thereby determines current performance 'profile', but I noticed a difference after I got the 'L' flash and reset it in the spring... it didn't last beyond a tank though, as the ECU remembered that I like to drive fast :D.
Old 12-01-2004, 10:25 AM
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I shift between 3500 - 4000 in everyday driving. Mileage is generally 15 - 16 overall (less than 1/2 highway). I routinely get 24 MPG on highway running 75MPH in sixth (still shifting around 4000)
Old 12-01-2004, 10:28 AM
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Thanks for the info on the ECU pump stuff...
Old 12-01-2004, 10:31 PM
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Originally Posted by amartin
I drove 170 miles @ ~80mph w/no AC, ambient temp was ~65 degrees outside.

Result: 18.9mph... thats 100% Highway w/no AC.
Just completed a 750 mile trip over the holidays. Driving conditions varied from stop and go on the interstate to mile after mile of 80-85 cruising speeds. Hit over 90 a couple time passing line of trucks. Used A/C very little. Result? 21 MPG average. OAT varied from 26F to a high of 56F (dense air).

After this trip, I believe my 8 would achieve the EPA estimate of 24 if I could just cruise at 65-70 MPH.

1.3L [MT]
Old 12-01-2004, 10:36 PM
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y talk about mpg again?! do u guys know.. our 8 got a even worst mpg than vette !!!!
when i told my firend the mpg of my 8 like 17mpg.. he laugh my *** off.!! so sad.. and his z06 got like 18mpg he said.. just wanna to say this world so crazy.!! hum...
let c.. a 2-hand z06 maybe a good choice..
Old 12-01-2004, 10:44 PM
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Originally Posted by Rxdriftingaction
y talk about mpg again?! do u guys know.. our 8 got a even worst mpg than vette !!!!
when i told my firend the mpg of my 8 like 17mpg.. he laugh my *** off.!! so sad.. and his z06 got like 18mpg he said.. just wanna to say this world so crazy.!! hum...
let c.. a 2-hand z06 maybe a good choice..

OMGWTFBBQ!!!?

That was painful to read. My eyes hurt.

English is a great language. Learn to use it.
Old 12-01-2004, 11:46 PM
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Originally Posted by dragula53
OMGWTFBBQ!!!?

That was painful to read. My eyes hurt.

English is a great language. Learn to use it.
Spanish rocks! :D
Old 12-04-2004, 07:39 PM
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gas

well i filled up the tank about three or four nights ago until it clicked off. I wanted to try driving the car under 3-4 grand just to see how the MPG was and after about half a tank of the shifting at 3 grand i got sick of it and shifted at the normal 5-6. I am now 3 notches above the 1/4 mark and have only gotten 100.5 miles...now i know i was getting better milage then that when shifting at higher RPM'S so what gives with getting worse mpg? and the build date on the car was aug of 2003. thanks again guys, not too pissed off about the MPG just wondering why it would have gone down, and how in the hell i am getting absolute horrible MPG.
Robert


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